The two leading Republican candidates for U.S. Senate in California are Duf Sundheim of Santa Clara County, and Tom Del Beccaro of Contra Costa County. According to this Orange County Register newspaper story, the two candidates publicly disagree on whether the California top-two system is good policy or bad policy. Sundheim helped pass the top-two system in 2010, whereas Del Beccaro opposed it.
It is rare for California elected officials, or major party candidates, to comment on California’s top-two system. As far as is known, Governor Jerry Brown has never said anything in public about Proposition 14.
Both Sundheim and Del Beccaro are former state Republican Party chairs.